1. Field of the Invention
The present invention relates to a method and apparatus for measuring a moving picture response curve based upon an image of a moving picture on a display to be measured (also referred to as the “target display”) that is captured by a moving picture color camera.
2. Description of Related Art
In order to evaluate the blurriness of a moving picture (also referred to as “moving picture blur”) on a display, measurements need to be made by moving a camera so as to pursue the moving picture like human eyeballs.
There is a known device (which is referred to as “moving picture camera”) for capturing pursued images of a moving picture by rotating a galvanometer scanner provided with a mirror in accordance with the moving speed of the moving picture.
This image capturing device captures pursued images of a picture while the picture is scrolled from left to right. A graph is plotted by converting CCD pixels in the moving direction of the captured image into a time axis as the abscissa, and taking RGB received intensity as the ordinate. The resultant curve is referred to as an MPRC (Moving Picture Response Curve). Based on the edge shape of this MPRC, an MPRT (Moving Picture Response Time) is determined. Objective evaluations of the moving picture blurs can be made using this MPRT.
When a moving picture response curve is obtained as a result of pursuit-capturing a moving picture by a color camera, a coloration phenomenon is observed at the edge part.
It has been known that, in the case of a field sequential drive display for example, in its principles, the light emitting timings for the elements of the respective colors are shifted for each RGB, so that a coloration phenomenon (which is called “color breakup”) occurs at the edge part of the displayed moving picture. This is because the display timings are shifted even though the moving picture response time is the same for each color.
In the cases of plasma displays and liquid crystal displays, color blurring occurs because the moving picture response time varies depending on the color of each display element. For example, in a plasma display, due to the differences in response speed and persistence of a phosphor among RGB colors, a bluish tone appears during a black to white transition, and a yellowish tone appears during a white to black transition. For this reason, color breakup occurs at the moving picture edge part.
Thus, in performing a comparative evaluation between displays, it is desired to obtain a moving picture response curve for every lighting color of a target displays.
It is an object of the present invention to provide a method of measuring a moving picture response curve that enables objective and quantitative evaluations of color shifting by decomposing the coloration at an edge of a pursuit-captured moving picture image into the respective component colors.